Research On MIMU/GPS Integrated Navigation System Of UAV

With the maturing of MEMS technology, the precision of micro-inertial sensors and MIMU is getting better. Although comparing with the precision of the conventional devices, there are still some gaps. However, due to the high-precision INS’s price is more expensive, under the circumstances requiring low power consumption, small size and low cost, the MEMS devices are becoming more widespread.Integrated navigation is the result of the development of modern navigation and technology. Each single navigation system has its own unique properties and limitations. By integrating several single systems together, sharing more information sources, complementing each other, we can get a higher redundant system which has a higher navigation accuracy. The complementary nature of the inertial navigation system and GNSS made INS/GNSS integrated navigation system becoming a mainstream way of navigation.The short-term errors of INS are relatively small, but they will continue to increase with the time; GPS’s short-term errors are worse than INS, but they don’t accumulate over time. By the Kalman filter, they can be integrated, and a good complement can be achieved. MIMU combine with the GPS navigation system can effectively improve the precision and stability of the navigation system, as a kind of new SINS.In this paper, for navigation application of UAV, MIMU/GPS integrated navigation system is designed, the key technologies are completed, and the hardware circuit based on FPGA is finished.Firstly, based on the analysis of GPS carrier positioning technology, according to the order of the signal processing in the GPS software receiver, the process and related principles of signal capture, signal tracking and data code solving are described in detail. Comparing with the hardware receiver, the flexible software is much easier to achieve GPS and MIMU ultra-tight integration.Secondly, in response to MIMU, this paper studied the the basic principles and components of SINS, provided the basic equation of the SINS, and did a simulation analysis about the SINS. With the in-depth understanding of GPS and MIMU, this paper analized the three integrated mode of the GPS/MIMU integration system, and completed the design of GPS/MIMU integrated navigation system’s discrete Kalman filter, completed the simulation analysis of the data fusion algorithm of the integrated navigation system.Finally, the paper selected Altera Cyclone II series FPGA chip EP2C8Q208C as the core of the integrated navigation system, ADIS16350as the micro inertial measurement unit, Maxim’s production single-chip GNSS receiver chip Max2769as RF front-end receiver chip, completed the hardware circuit of the integrated system, and the process of the integrated navigation system software is given.